1. Field of the Invention
The present invention relates to a control apparatus for an operation panel including an operation unit operable for operating an apparatus and a display unit for displaying a state of the apparatus, and an electronic apparatus including the operation panel.
2. Description of the Related Art
An electronic apparatus has an operation panel which includes an operation unit for inputting information with which a user operates an apparatus, and a display unit for informing a user of the state of the apparatus (operational state). In order to control the key matrix of the operation panel, a signal is input from the key matrix to the input port of a microcomputer (Japanese Patent Application Laid-Open No. 7-152468).
However, a control unit such as a microcomputer (CPU) and an application specific integrated circuit (ASIC) control a display device other than the key matrix such as a light-emitting diode (LED) and a liquid crystal display (LCD).
For example, the LCD is used to intelligibly display the operational condition and state of the electronic apparatus. The LED is used to indicate error status of the apparatus. In the operation panel, an operation switch is provided other than the display unit described above. Accordingly, many output terminals (ports) allocated to the LCD and the LED, and many input terminals (ports) allocated to switches are necessary. An increase in a number of such terminals leads to an increase in a number of signal lines which are linked to terminals.